Question

3. A centrifugal pump performance data are shown in the following table for water. Pump speed 2500 RPM Pe or P2 (bar) P or Pi (bar) Volume of water (L) Time (sec) Input-Power (W -0.3 20 60 100 For this data set, calculate the following: i. Pump discharge capacity Q (L/s and GPM) ii. Pump head H (m and f) iii. Fluid power Pr(Watt) iv. Brake power Pb (Watt) v. Pump overall efficiency η (%) vi. Flow rate coefficient Ca (or dimensionless specific capacity) vii. Head coefficient Ch (or dimensionless specific head) viii Power coefficient Cp (or dimensionless specific power) [3 points] [3 points] 3 points] [1 point] [1 point] 3 points] [3 points] [3 points] ix. If this is the maximum pump efficiency, the specific speed of the pump. [3 points] 1 Gallon -3.78541 Liters, 1 bar 100,000 Pa Suction pipe diameter and discharge pipe diameter are equal, the height difference between suction pressure gauge and discharge pressure gauge 0 Efficiency of the motor 90% Pump impeller diameter 100 mm

Answer 1

P_d=1 bar = 750.062mm of Hg

P_s= -0.3bar = -225.018mm of Hg

V=20L T=60sec

Q=V/T = 0.333L/sec

$H=\frac{(P_d-P_s)*\rho_m}{1000*\rho_w}$

H=13.2611 m of water

$P_f=\frac{9.81*H*Q*\rho_m}{1000*\rho_w}$

P_f=0.58916 Pa

$P_b=\frac{P_f}{\eta}$

P_b=0.654 Pa